1. Technical Field
This invention relates to over the road transport trailers that are used to transport ISO type containers from a rail head to a dump site.
2. Description of Prior Art
Prior art devices of this type have heretofore been directed to so called roll off dumpsters in which a flat bed trailer receives a bulk container, and unloads the contents by elevation of the bed and roll off of the container. Other design configurations move the container to the end of the trailer then elevate same dumping the contents without removing the container from the trailer bed, see for example U.S. Pat. Nos. 2,815,980, 4,954,039 and 5,007,791.
In U.S. Pat. No. 2,815,980 a dump trailer is disclosed wherein the dump body is mounted on a frame for rolling movement longitudinally so that when the frame is elevated the dump body will be positioned i.e. moved rearwardly for ease of dumping off the end of the frame.
U.S. Pat. No. 4,954,039 is directed towards a uniframe roll off dumpster in which a container is movably positioned on a dump frame so that upon elevation of the frame the container will roll off same thus unloading the container from the trailer.
U.S. Pat. No. 5,007,791 refers to an ISO container handling system wherein a two-part trailer frame is used to engage, elevate and roll off the ISO container. The two-part frame consist of a wheel support structure and a separate pivotable container engagement frame.